Valveless fluid pump

ABSTRACT

A driven fluid oscillator pump with no mechanical valves. Fluid flow is directed into a capacitance chamber of a modified RCR fluid oscillator and expelled such that a pulsed pumping action results. There are no valves in the pump, thus permitting corrosive and other such fluids to be pumped without damage or breakdown. The pump incorporates a fluid diode to prevent backloading of the capacitance chamber when it is expanding.

United States Patent 1191 Wortman Dec. 25, 1973 VALVELESS FLUID PUMP [76] Inventor: Donald E. Wortman, 609 Muriel St., Pmfmry 'f Husat Rockville Md. 20852 Assistant Exammer-Leonard Smith Attorney-Edward J. Kelly et al. [22] Filed: May 30, 1972 1 1 pp 257,736 57 ABSTRACT A driven fluid oscillator pump with no mechanical U.S. valves flow is directed into a capacitance cham- [51] Int. Cl. F04b 39/10, F15c 1/08 her f a difi d RCR fl id oscillator and expened [58] Field 01 Search 417/472, 557; Such that a pulsed pumping action results There are 137/826 830 no valves in the pump, thus permitting corrosive and other such fluids to be pumped without damage or [56] References Cited breakdown. The pump incorporates a fluid diode to UNITED STATES PATENTS prevent backloading of the capacitance chamber when 2,068,392 1 1937 Acker 417 557 it is expanding 3,041,980 7/1962 Behrens 417/557 3,409,184 11/1968 Stengle 417 472 x 4 Clam, 1 i g OUTPUT VALVELESS FLUID PUMP RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured, used, or licensed by or for the United States Government for governmental purposes without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fluid pumps, and more particularly, to fluid pumps that maintain a gentle valveless pumping action.

2. Description of the Prior Art Earlier embodiments of pulsatile pumps are dependent for their operation upon a multitude of moving parts such as valves and pistons. Such devices are not suited for prolonged service; valves tend to wear out, leak, and lose their efficiency while piston type displacement pumps tend to exert large compressive forces upon the fluid being pumped which precludes their use in pumping corrosive or explosive fluids. Additionally,such pumps tend to damage sensitive fluids such as blood.

It is therefore a primary object of the present invention to provide a fluid pump that utilizes no mechanical valves.

An additional object of the present invention is to provide a valveless fluid pump that provides a pulsatile output flow at any desired frequency.

A further object of the present invention is to provide a fluid pump in which sledge, brackish water, corrosive, explosive, or other easily damaged fluids such as blood will be pumped efficiently and safely.

SUMMARY OF THE INVENTION Briefly, in accordance with the invention, a valveless fluid pump is provided which comprises an input conduit for receiving the fluid to be pumped, an output conduit, an expansible chamber for collecting the input fluid, means for collapsing said expansible chamber causing it to empty, and a fluid amplifier system which will divert the outcoming fluid flow from the expansible chamber to the output conduit. The device also includes a fluid diode arrangement which prevents fluid from being sucked into the outlet conduit by the expansible chamber when it is also drawing fluid from the input conduit.

BRIEF DESCRIPTION OF THE DRAWING The specific nature of the invention as well as other objects, aspects, uses and advantages thereof will clearly appear from the following description and from the accompanying drawing, in which;

The FIGURE is a diagrammatic sketch of a preferred embodiment of the fluid pump in accordance with the present invention.

DESCRIPTION OF THE PREFERRED. EMBODIMENT Referring now to the drawing, it is seen to represent a preferred embodiment of the fluid pump of the present invention. The input conduit leads to an interaction region formed by the intersection of input conduit l0, resistanceconduit 12, control conduit 18, and exhaust conduit 22. It is seen that resistance conduit 12 leads to an expansible bellows chamber 14 that serves as a capacitance tank for the device. Connection I6 illustrates a manual or mechanical connection to a suitable device well known in the art that will drive bellows 14 at the desired frequency of operation. Exhaust conduit 22 leads to output conduit 24 from which the pulsed fluid will flow. Between exhaust conduit 22 and output conduit 24 is interposed a fluidic diode that has a control conduit 26, an interaction region 28, a circulating conduit 30 and an outlet 32. The diode may also include a flexible membrane 34 along its outer wall to provide a greater capacity to contain fluid.

In operation, fluid enters input conduit 10 and flows normally through interaction region 20 to enter resistance conduit 12 and fill up capacitance tank 14. This is occurring as bellows 14 is expanding by virtue of an upward force being applied to linkage 16. During this phase of filling, the problem exists of preventing fluid from entering output conduit 24 and being drawn up through resistance conduit 12 to also fill capacitance tank 14. However, the fluid diode as prescribed above prevents this from happening in the following manner. A portion of any fluid that will be drawn into output conduit 24 will enter control conduit 26 of the diode and exit therefrom into interaction region 28. The exiting fluid will impinge upon the remainder of the fluid flowing through output conduit 24 toward interaction region 20 and will force it to enter circulation conduit 30. If membrane 34 is present, it will expand as a result of the fluid entering circulating conduit 30 until such time as a certain predetermined volume is attained, after which it will exert a motive force on such accumulated fluid to force it out outlet 32 and thus shift the flow of fluid back out output conduit 24. At the very worst, a portion of the fluid exiting output channel 32 will reenter control conduit 26 and the foregoing cycle will repeat itself. It is thus seen that in the foregoing manner, capacitance tank 14 will be free from any fluid present at output conduit 24 while it is drawing fluid from input conduit 10. After tank 14 has received the required amount of fluid, as predetermined by the particular use of the fluid pump, a force will be exerted via linkage 16 to collapse chamber 14 and force the fluid to exit along resistance conduit 12. It is seen from the FIGURE that a portion of this fluid exiting will circulate thru control conduit 18 This portion will impinge upon the portion exiting along resistance conduit 12 at interaction region 20 and force the main flow to traverse the path defined by exhaust conduit 22, eventually leaving thru output conduit 24 to complete one pulsed cycle of the fluid pump.

The foregoing action of resistance conduit 12, capacitance tank or bellows 14, and control conduit 18 is akin to an RCR fluid oscillator. The pump of the present invention will be ideal for special situations wherein mechanical valve failure is often a problem or where gentle pumping action is a prerequisite for the pumps characteristics. It might be specially suited for pumping a substance like blood, corrosive fluids, or volative substances. For pumning blood, for example, the pumps may be arranged in a backto-back configuration wherein the wall 15 would separate two bellows-like expansible devices on either side and would thus simulate the action of the natural heart. In order to pump like an artificial heart, the present invention would have to be driven at the necessary frequency.

I claim:

1. A valveless fluid pump, comprising:

a. an input conduit for receiving the fluid to be b.asecond control conduit adapted to receiveaporpumped; tion of any fluid that is drawn into said output conb. an output conduit that provides an exit path for the duit while said collecting means is receiving fluid pumped fluid; from said input conduit, said second control conc. expansible means for collecting the fluid from said 5 duit adapted to direct said portion of fluid it reinput conduit; ceives to impinge upon the other portion of fluid d. means for collapsing said collecting means to entering said output conduit so as to divert its flow empty the fluid collected therein; and into said circulating conduit which delivers the e. a first control conduit for receiving a portion of the fluid so diverted back out through said output confluid exiting from said collecting means and for diduit. recting said portion so as to impinge upon the re- 3. The pump claim 2 wherein said collecting means maining portion of fluid exiting from said collecting comprises a bellows device. means so as to divert its flow towards said output 4. The pump of claim 3 wherein said circulating conconduit. duit further comprises an expansible wall so as to col- 2. The pump of claim 1 wherein said ensuring means lect said diverted fluid, said wall collapsing upon the comprises: attainment of a certain volume of fluid therein to proa. acirculating conduit whose input and output openvide a motive force for directing said diverted fluid ings are in communication with said output conback out through said output conduit. duit; and 

1. A valveless fluid pump, comprising: a. an input conduit for receiving the fluid to be pumped; b. an output conduit that provides an exit path for the pumped fluid; c. expansible means for collecting the fluid from said input conduit; d. means for collapsing said collecting means to empty the fluid collected therein; and e. a first control conduit for receiving a portion of the fluid exiting from said collecting means and for directing said portion so as to impinge upon the remaining portion of fluid exiting from said collecting means so as to divert its flow towards said output conduit.
 2. The pump of claim 1 wherein said ensuring means comprises: a. a circulAting conduit whose input and output openings are in communication with said output conduit; and b. a second control conduit adapted to receive a portion of any fluid that is drawn into said output conduit while said collecting means is receiving fluid from said input conduit, said second control conduit adapted to direct said portion of fluid it receives to impinge upon the other portion of fluid entering said output conduit so as to divert its flow into said circulating conduit which delivers the fluid so diverted back out through said output conduit.
 3. The pump claim 2 wherein said collecting means comprises a bellows device.
 4. The pump of claim 3 wherein said circulating conduit further comprises an expansible wall so as to collect said diverted fluid, said wall collapsing upon the attainment of a certain volume of fluid therein to provide a motive force for directing said diverted fluid back out through said output conduit. 